Scavenging slugs, such as Umax maximus (Plate 

 70) may reach a length of 8 inches. They can pro- 

 tect themselves by spurting out jets of milky mucus 

 quite unlike the colorless, transparent film they se- 

 crete over the body surface and beneath the foot 

 while traveling along. Until the mucus trail becomes 

 covered with dust, the path of a snail or slug on land 

 can usually be followed as a glistening ribbon. In 

 places it may remain as a vertical rope, showing 

 where the animal crept to the end of a leaf or twig, 

 then let itself down in slow motion on a strand of its 

 own secretion — like the Indian rope trick in reverse. 



Land snails and slugs have a pair of eyes, each at 

 the tip of an upper, retractile tentacle. If touched, the 

 tentacle is inverted like a glove finger, pulling the 

 eye down into the safety of the head. Yet if some 

 animal nips off an eye-bearing tentacle, the mollusk 

 can regenerate a new one. 



Pond snails, by contrast, wear their eyes at the 

 base of the single pair of tentacles on the sides of the 

 head. These tentacles cannot be withdrawn, al- 

 though they appear in position to correspond to the 

 lower, retractile pair on land snails and slugs. 



The custom of eating land snails in Italy antedates 

 the Christian era. Snails became a delicacy in France 

 in the latter part of the eighteenth century. Now 

 Paris is the center for them, with more than two 

 hundred million snails consumed annually during 

 the season from September to April. Most of these 

 are Helix poinatia, raised on vegetables and bran 

 mash in snail gardens or snaileries fenced with wire 

 netting — about ten thousand snails to each pen 

 twenty-five or thirty feet square. No market of com- 

 parable size has been found for them in any other 

 part of the world. 



Shell collectors everywhere are attracted to a tree 

 snail of Cuba and isolated bits of higher land in 

 swampy parts of Florida and the Florida keys. These 

 are the homes of Liguiis. a tan-bodied animal with a 

 11/2 -inch banded shell the shape of a tear drop. 

 Every isolated colony seems to have its own color 

 pattern, although the diet in each is essentially the 

 same: fungi and lichens growing on the bark of sub- 

 tropical and tropical trees. During winter or ex- 

 tended dry weather, Llguiis cements the rim of its 

 shell to the bark and waits for a good rain that will 

 allow growth of its food plants. 



Among the largest of land snails (Plate 49), the 

 most famous today is Achatina jiilica, a native of 

 Mauritius and perhaps also eastern Africa from 

 Natal to Somaliland. These large snails weigh up to 

 a pound, part of this a sturdy brown shell marked 

 with streaks of purple, green, pink, or snow white. 

 Both very young and old Achatina snails feed on 

 decaying vegetation. But at intermediate ages they 

 are active at night, attacking living plants and scav- 



Common periwinkles, Littorina littorea, are gathered 

 in great numbers for use as food. The largest of Euro- 

 pean periwinkles, ihev live on the lower half of the 

 tidal shore. {North \Vales. D. P. Wilson) 



»» 

 ^ 



The eggs of the moon snail Polinices are embedded 

 in a nii.xture of mucus and sand, forming the "sea 

 collar" which is flexible enough while wet that waves 

 can cast it unharmed upon the beach. When the col- 

 lar becomes dry in the curio cabinet of a beach- 

 comber, it is extremely fragile. Its form matches the 

 upper surface of the foot of Polinices [see color plate 

 55]. (Massachusetts. Lorus and Margery Milne) 



enging only for dietary supplements. Within six weeks 

 each individual matures as a male, then changes to a 

 female and begins laying batches of as many as three 

 hundred pea-sized eggs month after month. A con- 

 servative estimate of over a billion offspring from 

 each gravid female in five years could be translated, 

 at a pound apiece, into more than half a million tons 

 of mollusks, representing a frightful toll of vegetation. 

 In its African homelands, quite a number of differ- 

 ent animals prey on Achatina fulica. Native people 

 prize the snails as food and their shells as utensils 

 and the raw material from which to carve spoons. 



